Nuances of Turing test requirements
I do not know about all competitions, but the Loebner prize is one of the more well known competitions based around the concept of the Turing Test, specifically for chatbots, and judges must ask the same questions of all bots. The questions are only revealed during the competition, it is not possible for bot programmers to prepare for them other than making a generally good chatbot. They judges can then rank bots on how they handle the same set of questions. E.g. from chatbots.org/ai_zone/viewthread/867 here are the 2012 &quot;qualifying&quot; questions that were released following the test:

My name is Bill. What is your name?
How many letters are there in the name Bill?
How many letters are there in my name?
Which is larger, an apple or a watermelon?
How much is 3 + 2?
How much is three plus two?
What is my name?
If John is taller than Mary, who is the shorter?
If it were 3:15 AM now, what time would it be in 60 minutes?
My friend John likes to fish for trout.  What does John like to fish for?
What number comes after seventeen?
What is the name of my friend who fishes for trout?
What whould I use to put a nail into a wall?
What is the 3rd letter in the alphabet?
What time is it now?

According to the WikiPedia description, the style of the questions has changed over time. The above set in my opinion seem to be designed to test very simple grammar, common sense and memory targets.